|Tumours can spring up amongst|
'fields' of healthy skin cells.
The summer sun may finally be on its way. This is great news for barbecue kings and beach bums but also for the weeds lurking below the surface of the soil popping up intermittently to strangle my carrots.
New research published in Cell describes another reason to cake ourselves in sun cream, cover up our bare flesh and wear ridiculously wide-brimmed hats in the coming months: weed-like skin cancers which start below the surface of the skin and grow upwards.
"Too much sun" is well known to carry a risk of skin cancer. Prolonged exposure to the sun's Ultraviolet (UV) rays can wither the DNA in cells on the skin's surface sometimes causing multiple tumours to spring up at once.
Dr Bing Hu and colleagues found alarming evidence that some cancers may start much deeper in the tissue. This may explain why skin cancers frequently reappear: surgery may remove a tumour, but its roots may remain.
The new research suggests that skin cancer can be kick-started by changes in the dermis – deeper skin tissue where healthy cells reproduce to replenish the cells on the surface.
The team, from the University of Lausanne in Switzerland, discovered that UV light can cause mutations in the wiring of dermal cells, specifically to a protein called 'Notch' which is necessary for individual skin cells to communicate.
They found that mice born with malfunctioning Notch develop severely distorted skin full of lesions and tears. The dermal skin cells of these mice displayed accelerated cell division, a common prelude to tumour formation.
The mouse studies gave the team a vital clue of what to look for in human cells. They have since discovered Notch is disrupted in some human skin cancers too.
Dr Hu says that designing drugs to protect or repair Notch in human cells might be used in “preventing or reversing” the unseen effects of the sun on cells under our skin.
Until then, whether you're weeding, barbe-ing or bathing this summer the advice remains the same: enjoy responsibly. And remember to buy ice. And fire-lighters.
Hu B, Castillo E, Harewood L, Ostano P, Reymond A, Dummer R, Raffoul W, Hoetzenecker W, Hofbauer GF, & Dotto GP (2012). Multifocal Epithelial Tumors and Field Cancerization from Loss of Mesenchymal CSL Signaling. Cell, 149 (6), 1207-20 PMID: 22682244